Polydiacetylenes, a class of polymers obtained by the polymerization of diacetylene monomers (organic molecules containing two carbon-carbon triple bonds), exhibit two distinct absorption bands in the visible region. The art has suggested numerous detection methods for various chemical and biological analytes, based on the unique property of polydiacetylenes to undergo a visible color change from blue to red following a structural perturbation in their electronic conjugated backbone, which perturbation is generated by the analytes to be detected.
WO 98/39632 suggests the use of polydiacetylenes for detecting membrane conformational changes. In particular, membrane modifying reactions and analytes responsible therefore are discussed in said publication.
WO 99/10743 describes the encapsulation of polydiacetylenes into metal oxide glass, and the use of the transparent composite obtained for the detection of various analytes.
WO 00/55623 discloses a beneficial combination of polydiacetylenes, lipids and suitable means linked thereto for detecting the presence of analytes in a liquid sample, wherein said analytes cannot react chemically with said polydiacetylenes and lipids. Specifically mentioned analytes include metal ions, biological ligands and peptides.
U.S. Pat. No. 6,361,962 describes a multi-type toxin indicator which may comprise polydiacetylenes for detecting the presence of bacteria in foods.
U.S. 2002/0034475 discloses the incorporation of polydiacetylenes into various food products. The polydiacetylenes undergo a chromatic color transition in response to various triggering mechanisms such as temperature change, pH change, mechanical stress and the presence of bacteria in the food.